In short, RI represents resistance based on blood flow. A higher RI indicates higher resistance.
Generally, when expressing resistance, the range of change (maximum minus minimum) is divided by the mean value. However, this RI divides by the maximum value. This follows the RI that was theoretically established with Doppler flowmetry, and was implemented as a parameter in LSFG for comparison purposes. Since it divides by the maximum value, changes in resistance are larger compared to dividing by the mean value.
RI (Resistivity Index) is the value obtained by dividing the difference between the maximum and minimum MBR values by the maximum MBR value.
